it will be surprising

English as a Second Language English Vocabulary, Grammar and Idioms
1

Which are correct:

[color=red]1-I don’t know if they helped John last night or not, but it would be surprising if they did.
[color=indigo]2-I don’t know if they helped John last night or not, but it will be surprising if they did.

[color=red]3-It would be surprising if they helped John last night, but that might be what they did.
[color=indigo]4-It will be surprising if they helped John last night, but that might be what they did.

Gratefully,
Navi.

2

#1 and #3 seem grammatically correct to me.
Between the two, I prefer #1.

3

I would say something like:

I’d be surprised if they helped John last night, but you never know.

I don’t know if they helped John last night, but I’d be surprised if they did.

something like that… “I’d be surprised” is more natural than “it would be surprising”